1. Field of the Invention
The invention relates to the field of aircraft ferrying aircraft and, in particular, to a system wherein a transport aircraft ferries aircraft by attaching the aircraft to be ferried to its wing tip.
2.Description of Related Art
The concept of ferrying aircraft aboard other aircraft is very old in the art. In the 1920s, dirigibles were designed to ferry aircraft attached to the gondola. The advantage of ferrying and aircraft is that it could serve as a scout for the dirigible or provide protection. In the 1940""s small aircraft were suspended under larger bombers. Here the ferried aircraft was typically a fighter, which could be used for protection against hostile aircraft. The problem with such ferrying systems is that the weight of the ferried aircraft limited the payload carrying capacity and/or the range of the ferrying aircraft.
It has long been known that the aerodynamic efficiency of an aircraft can be increased by the incorporation of wing tip devices that prevent or reduce the wing tip vortexes. Thus wing tip fuel tanks installed on the P-80 improved the aerodynamic efficiency to such a degree that tip tanks were xe2x80x9cflown for freexe2x80x9d, in that the increase in aerodynamic efficiency offset the drag and weight penalty. In the early 1950s an attempt was made to ferry small fighter aircraft on the wing tips of a larger aircraft. F-84 fighter aircraft were successfully flown attached to the wing tips of a B-36 bomber. The F-84 aircraft were again almost flown for xe2x80x9cfreexe2x80x9d. However, there were problems attaching the two aircraft together and in-flight stability was difficult to maintain. The pilots of the F-84 aircraft flew xe2x80x9chands offxe2x80x9d once attached to the B-36. Thus only the B-36 flight control effectors such as ailerons, elevators, rudders, etc., were used. After several crashes, the flight test program was terminated in part because of these problems. Additionally, air-to-air refueling became practical.
However, in flight refueling requires the use of dedicated refueling aircraft. With the advent of unmanned aircraft, there is a new need to ferry such aircraft. Most recently, NASA has flown aircraft in close proximity to take advantage of the reduction in drag that such formation flying offers. Both aircraft remain separated, however and their propulsion systems remain the main source of power for flight.
Thus, it is desirable to provide an efficient system to ferry aircraft.
It is further desirable to provide an efficient system to ferry aircraft without significantly compromising the performance of the ferrying aircraft.
It is still further desirable to provide an efficient system to ferry aircraft wherein the ferried aircraft are attached to the wing rips of the ferrying aircraft and stability and aerodynamic loads of all the aircraft is controlled by the ferrying aircraft.
A system for and method of ferrying a least one aircraft by a ferrying aircraft is provided. In one embodiment, the system includes an attachment device for joining a wing tip of the at least one aircraft to one of the wing tips of the ferrying aircraft and a system for controlling the at least one aircraft and the ferrying aircraft, such that the at least one aircraft flight characteristics are controlled by the ferrying aircraft. Preferably, the ferrying aircraft will have an aircraft joined to each wing tip, which will provide improved efficiency. Movement of the aircraft""s effectors controls the flight characteristics of the ferried and ferrying aircraft.
The system for controlling the flight characteristics includes the ferrying aircraft having a first effector commend system, a first vehicle management system is coupled to the first effector system; a signal transmission system is included to transmit signals from the first vehicle management system to the ferried aircraft. The ferried aircraft include: a second vehicle management system; a system to receive transmitted signals from the ferrying aircraft""s vehicle management system; a second effector command system coupled to the ferried aircraft vehicle management system; and a switch mechanism for disconnecting the ferried vehicle management system from its effector command system and coupling the effector command system to the system to receive transmitted signals from the ferrying aircraft.
The first vehicle management system includes: a first control system program for controlling the first effector command system of a ferried aircraft attached to only the right wing of the ferrying aircraft; a second control system program for controlling the first effector command system of a ferried aircraft attached to only the left wing of the ferrying aircraft; a third control system program for simultaneously controlling the first and second effector command systems of ferried aircraft attached to both wings of the ferrying aircraft; and fourth control system program for controlling the ferrying aircraft when no aircraft are attached. In addition sensors mounted in the attachment means on the wing tips sense whether an aircraft is attached and provide a signal to the first vehicle management system. Such that the proper control system program can be selected.
The method includes the steps of: flying the at least one aircraft to be ferried to the ferrying aircraft; joining a wing tip of the at least one aircraft to be ferried to the wing tip of the ferrying aircraft; and controlling the flight characteristics of the joined aircraft such that the ferried aircraft are controlled by the ferrying aircraft.
The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description in connection with the accompanying drawings in which the presently preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention.